They're based on the results of your testing.
Carbon dioxide is created when hydrolic is mixed with calcium carbonate.
Answer:
Led is a light-emitting diode, a semiconductor diode that glows when a voltage is applied. So, there is always a sure result of whether a substance conducts electricity or not as the light glows. That is why it is a better option for testing conduction of electricity.
Explanation:
KCI is not a covalent compound, it is an ionic compound.
A covalent compound is one in which each of the atoms involved contribute a specific number of electrons for sharing in order to from stable compound while an ionic compound is a compound formed when one atom donates electron to the other atom in the compound, in order to attain stability. The compounds given in options A, B and D shared electrons while in KCl, potassium donates an electron to chlorine.
